RESEARCHES  ON  THE 
STRUCTURE  OF  ANTHRACENE 


By 

ERNEST  ATKINS  WILDMAN 

B.S.  Earlham  College,  1912 
M.S.  University  of  Illinois,  1914 


THESIS 

SUBMITTED  IN  PARTIAL  FULFILLMENT  OF  THE  REQUIREMENTS 
FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY  IN  CHEMISTRY 
IN  THE  GRADUATE  SCHOOL  OF  THE  UNIVERSITY 
OF  ILLINOIS,  1922 


URBANA,  ILLINOIS 


\'~3 


UNIVERSITY  OF  ILLINOIS 


THE  GRADUATE  SCHOOL 


May  12 


192- 


I HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 
SUPERVISION  BY ERHB8T  ATKINS  WILDMAK 


ENTITLED  RESEARCHES  OH  THE  STRUCTURE  Qg  ANTHRACENE 


BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 


THE  DEGREE  OF  Doctor  of  Philosophy 


UC A 


/ In  Cl 


n Charge  of  Thesis 


uC  A AT* 


H^ad  ot  Depa 


partment 


Recommendation  concurred  in 


in* 


Committee 


on 


Final  Examination^ 


A C'OAQO 


CONTENTS. 

I.  THEORETICAL  DISCUSSION  page  1. 

II.  DEJECT'  OF  THIS  RESEARCH  page  7. 

III.  DISCUSSION  OF  THE  EXPERIMENTAL  PART  page  S. 

IV.  EXPERIMENTAL  PART  page  14. 

V.  BIBLIOGRAPHY'  page  26. 


Digitized  by  the  Internet  Archive 
in  2016 


https://archive.org/details/researchesonstruOOwild 


X 


I.  THEORETICAL  DISCUSSION. 

It  is  the  general  opinion  of  chemists  that  the 
structure  of  anthracene  is  represented  either  by  Formula  I. 
or  by  Formula  II. 


I . II . 


These  have  been  called  the  meso-linkage  or  the  bridge  formula, 
suggested  by  Graebe  and  Liebermannx , and  the  aromatic  or 
ortho-quinoid  formula,  suggested  by  Armstrong",  respectively. 

3 

Kurt  Meyer  considers  that  it  is  altogether  improbable  that  there 
can  exist  a rearrangement  or  isomerism  between  these  two  forms 
and  therefore  that  they  are  not  different  phases  of  the  same 
formula. 


Of  the  several  known  syntheses  of  anthracene  none  of 
those  that  involve  the  intermediate  formation  of  dihydro- 
anthracene or  of  anthraquinone  are  of  any  value  in  deciding 
between  the  above  two  formulas.  There  is  no  evidence  of  the 
disposition  made  of  the  valencies  of  the  meso  carbon  atoms  during  j 
either  oxidation  of  dihydroanthracene  to  anthracene  or  reduction 
of  anthraquinone  to  anthracene.  The  only  synthesis  that  is  free 
from  this  objection  is  that  of  Anschutz  and  Elsbacher  by  means 
of  the  Friedel  and  Crafts  reaction  using  benzene  and  tetrabromo- 

ethane  ^ 

/3a  -c-  <J lx. 

-f  I -+- 

rw  c-ox, 

i 

H 


2 


While  this  synthesis  seems  to  be  an  indication  in  favor  of  the 
meso- linkage  formula  it  is  nevertheless  discredited  by  some 
authorities,  as  Meyer  and  Jacobson's  Lehrbuch^  on  the  basis  that 
aluminium  chloride  is  a reagent  that  may  cause  a rupture  of 
linkage  between  carbon  atoms  as,  for  example,  in  the  reversal  of 
the  Friedel  and  Crafts  reaction. 

Assuming  the  meso- linkage  formula  and  the  Kekule 
formula  for  the  benzene  ring  there  are  three  phases  depending  on 
the  positions  of  the  double  bonds: 


In  other  words  the  two  outside  rings  in  such  a formula  are  to  be 
considered  as  typical  benzene  rings  while  the  meso  carbon  atoms 
are  distinctly  alifatic  in  nature.  A more  proper  formula  to 
emphasize  this  fact  is 


true  we  should  expect  these  two  benzene  rings  to  have 
properties  of  benzene.  While  they  do  have  such  to  a 
extent  there  is  at  least  one  very  striking  exception. 
I , 4-anthraquinone 


is  a well  known  substance  and  1 ,2-anthraquinone 


If  this  is 
the  usual 
large 
Whereas 


3 


is  easily  prepared  by  gentle  oxidation  of  I ,2-dihydroxyanthracene , 

r* 

Lagodzinski0  found  that  2 , 3-anthraquinone , the  existence  of  which 
is  predicted  by  the  meso-linkage  formula,  is  not  produced  by  the 
oxidation  of  2 , 3-dihydroxyanthracene . The  fact  is  interpreted  as 
meaning  that  there  is  only  a single  bond  between  positions  2 and  3 
in  anthracene  and  that  this  single  bond  is  fixed  in  that  position. 
There  is,  consequently,  no  rearrangement  or  shifting  from  one 
phase  to  another  of  the  double  and  single  unions.  This  fact  cannot 
be  reconciled  with  the  mesoT linkage  formula  but  it  is  entirely 
compatible  with  the  ortho-quinoid  formula  in  which  there  is  such  a 
fixation  of  double  and  single  bonds.  It  is  true  a 2,3-quinone  may 
be  formulated  as  follows 


but  if  this  is  formed  from  2 , 3-dihydroxyanthracene  there  must  be 
a very  extensive  rearrangement  of  valence.  Lagodzinski  found  that 
mild  oxidizing  agents  did  not  affect  2 , 3-dihydroxyanthracene  and 
that  more  energetic  agents  completely  disrupted  the  molecule. 

7 

Hinsberg  has  found  that  the  stability  of  azines  with 
increasing  numbers  of  linearly  conjugated  rings  grows  less  with 
such  rapidity  that  the  five  ring  azine  is  not  capable  of  existence. 
The  synthesis  of  phenazine  from  ortho-phenylene  diamine  and  ortho- 
benzoquinone  indicates  that  without  doubt  the  nitrogen  atoms  are 
linked  in  the  ortho-quinoid  manner.  This  is  further  indicated  by 
the  intense  color  of  such  compounds  as  naphtho-phenazine  which  is 
probably  caused  by  the  accumulation  of  quinoid  linkages  as  shown 


i 


On  the  other  hand  the  stability  of  the  dihydrogenated  derivatives 
of  the  azines  increases  with  the  number  of  rings.  Both  these  facts 
are  to  be  expected  from  Baeyer's  strain  theory.  The  addition  of 
a ring  in  the  azines  is  in  fact  the  attachment  of  a four  atom 
conjugate  system  while  it  is  a true  benzene  ring  in  the  dihydro- 
genated compounds.  Their  stability  may  be  compared  to  that  of 
dihydrobenzene  and  benzene.  Hinsberg  believes  that  an  analogous 
reasoning  also  holds  for  anthracene  and  related  compounds. 

K.  H.  Meyer°f avors  the  ortho- quinoid  formula  since  it 
seems  more  in  accord  with  the  keto-enol  tautomerism  which  he  has 
demonstrated  exists  between  anthranol  and  anthrone . Furthermore 
anthranol  is  distinctly  phenolic  in  character,  a fact  which  is 
represented  by  the  ortho-quinoid  formula  whereas  the  meso-iinkage 
formula  indicates  the  hydroxyl  group  as  attached  with  the  typical 
union  of  the.  tertiary  alifatic  alcohol. 

Scholl^  has  obtained  several  reduction  products  of 
flavanthrene  in  which  either  one  or  both  anthraquinone  nuclei  are 
reduced.  He  found  that  the  ortho-quinoid  formula  for  anthracene 
must  be  assumed  in  order  to  formulate  the  reduction  products  in 
accord  with  their  properties.  Dihydrof lavanthrene  (VI)  forms  an 
addition  product  with  water  to  produce  the  mono-hydrate  (VII) 
which  is  acidic  and  forms  a sodium  salt.  If  the  meso-iinkage 


VI 


VII 


5 

formula  is  used  to  represent  the  mono-hydrate  the  compound 
formulated  should  not  have  acidic  properties.  The  evidence  in 
this  case  is  of  the  same  nature  as  that  referred  to  above  in 
connection  with  the  acidic  properties  of  anthranol. 

Schlencfcr  and  his  associates  have  produced  quite 
strong  evidence  of  the  ortho-quinoid  formula  in  showing  that 
anthracene  adds  metallic  sodium  very  readily  in  a manner  analogous 
to  the  ethylenic  hydrocarbons.  Schlenck  takes  the  position  that 
the  meso-linkage  formula  expresses  a condition  of  valence 
saturation  for  the  meso  carbon  atoms --presumably  analogous  to  the 
manner  of  linkage  in  cyclobutane- -and  that  therefore  the  fact  of 
the  addition  of  sodium  proves  the  existence  of  the  conjugated 
system  of  two  double  unions. 

Recently  von  Weinberg has  argued  from  the  basis  of 
heat  of  combustion  determinations  that  anthracene  is  completely 
conjugated  as  is  rather  generally  accepted  to  be  the  case  in 
benzene.  Such  a conclusion  is  in  harmony  with  the  ortho-quinoid 
formula  rather  than  the  meso-linkage  formula.  The  results  of 
another  physical  method,  that  is,  refractive  index  determination, 
point  in  the  same  direction.  Auwers"*"6  has  shown  that  meso- 
isoamylanthracene  has  refractive  and  dispersive  powers  much 

exalted  over  those  for  dihydr.o-meso- isoamylanthracene . 

13 

Finally  Colver  with  Noyes  have  synthesized  anthra- 
cene froin  naphthalene  by  means  of  a series  of  reactions  in  which 
a third  ring  was  built  up  on  a dihydronaphthalene  nucleus.  The 
work  is  in  harmony  with  the  ortho-quinoid  formula  although  it  is 
not  claimed  to  throw  any  positive  light  on  the  problem. 


The  ortho-quinoid  formula  was  early  recognized  by 


G 


Armstrong  as  unsymmetrical . While  there  is  sufficient  evidence 
from  several  syntheses  that  dihydroanthracene  and  anthraquinone 
are  symmetrical  there  is  no  proof  that  anthracene  is.  It  is  true 
that  anthraquinone  mono-sulfonic  acids  and  mono-amines  when  reduced 
to  the  corresponding  anthracene  derivatives  might  he  expected  to 
yield  two  isomers  if  an  unsymmetrical  structure  is  generated,  yet 
such  have  never  been  observed.  This  is  net  a weighty  objection, 
however,  for  the  chemistry  of  the  substitution  products  of 
anthracene  is  still  to  a large  extent  undeveloped  due  to  the  much 
greater  technical  importance  of  anthraquinone  derivatives. 


. 


' 


7 


II.  OBJECT  OF  THIS  RESEARCH 

This  research  is  "based  upon  the  supposition  that  if 
the  ortho-quinoid  structure  is  correct  it  should  be  possible  to 
oxidize  a proper  anthracene  derivative  and  obtain  as  the  result 
a derivative  of  naphthalene  in  much  the  same  way  as  Bamberger  and 

i A 

Praetorius  have  oxidized  anthragallol  and  obtained  hydroxy- 
alpha-naphthoquinone  acetic  acid.  It  is  the  opinion  of  the/ writer 
that  if  a naphthalene  derivative  were  obtained  in  this  way  from 
an  anthracene  derivative  the  result  would  be  quite  conclusive 
evidence  of  the  correctness  of  the  ortho-quinoid  formula. 

In  view  of  the  relative  ease  with  which  the  meso 
positions  of  anthracene  are  attacked  it  is  necessary  to  render  one 
of  the  outside  rings  more  susceptible  to  oxidation.  This  it  has 
been  hoped  to  accomplish  by  preparing  I , 2 , 3-trihydroxyanthracene , 
in  which  the  ring  containing  the  three  hydroxyl  groups  should  be 
readily  oxidized  with  the  probable  formation  of  haphthalene- 
2 , 3-d.icarboxylic  acid. 

There  is  also  included  a description  of  three  attempts 
made  several  years  ago  to  synthesize  anthracene,  one  of  which 
aimed  at  the  meso-lihkage  structure  and  the  other  two  at  the  orthc- 
quinoid  structure.  Since  none  of  these  were  successful  the  main 
part  of  the  work  has  been  that  outlined  above. 


6 


III.  DISCUSSION  OF  THE  EXPERIMENTAL  PART. 

Attempt  to  synthesize  the  meso-Iinkage  structure. 

Whereas  Anschutz  and  Elsbacher*  used  a method  which  has  been 
discredited  in  the  opinion  of  some  it  seemed  that  this  objection 
would  be  removed  if  instead  of  benzene , ortho-dibromobenzene  were 
condensed  with  tetrabromoethane  by  means  of  Fittig's  reaction. 

The  reaction  was  expected  to  take  place  at  least  in  part  as 
indicated  in  the  following  equation: 


The  ortho-dibromobenzene  used  was  prepared  according  to  the 


following  series  of  transformations: 


from  products  of  reaction. 


Attempt  to  synthesize  the  ortho-quinoid  structure 

from  alpha-naphthol  and  succinic  anhydride. 

7«Titt  and  Braun  have  prepared  l-hydroxy-2-acetonaphthalene 
by  the  action  of  acetic  anhydride  on  alpha-naphthol  in  the  presence 
of  zinc  chloride.  If  the  same  sort  of  condensation  is  of  general 
application  as  one  might  suppose  since  it  has  also  been  used  by 


9 


Hantzsch'1'  for  the  preparation  of  i-hydroxy-2-propionaphthalene , 
it  is  reasonable  to  expect  that  succinic  anhydride  might  also 
be  used  and  that  it  would  form  a product  as  shown  in  the 
equations  that  would  condense  further  to  i , 4 ,9- trihydroxy - 
anthracene.  This  result  was  not  realized  for  no  pure  substance 
could  be  isolated  from  the  tar  that  was  formed. 


C-H  do 

l y. 


Attempt  to  build  up  the  third  ring  with  ethane 
tetracarboxylic  ester. 


The  procedure  which  was  outlined  for  this  synthesis  is 
indicated  in  the  following  series  of  transformations  and  equations 


roV3E3SKZZKE2Ur3 


o 

rV>  _ h 

10 

1 

o 

H 

^1 

o H 

u 

II 

/\/ 

— > 

, H 
H 

kj 

ft 

0 

The  scheme  was 

carried 

o 

out  in  pra 

ct  ice 

to  the 

o\\ 

point 

of  attempting  to  condense  the  alpha-methoxy-beta-naphthoyl 
chloride  with  the  mono-sodium  salt  of  ethane  te tracer boxy lie 
ester  in  ether  solution.  There  //as  no  reaction.  The  work  v/as 
then  discontinued  and  when  several  years  later  the  original 
samples  were  examined  with  greater  care  it  was  found  that  they 
were  quite  impure  on  account  of  the  fact  that  the  hydroxy- 
naphthoic  acid  had  been  incompletely  methylated.  The  methoxy- 
acid  was  present  in  the  mixture,  however,  and  was  isolated  in 
pure  form  by  careful  fractional  crystallization.  The  synthesis 
ha§  not  been  carried  farther  in  view  of  the  decision  to  attempt 
the  degradation  of  an  anthracene  compound  to  a naphthalene 
compound . 

Degradation  of  anthracene  to  naphthalene. 

An  examination  of  the  literature  indicated  that  the  best 
method  of  preparing  I ,2 ,3-trihydroxyanthracene  is  probably  by 
demethylation  of  its  tri-methyl  ether  which  should  be  produced 
by  reduction  of  anthragallol  trimethyl  ether.  There  are  two 
methods  on  record  for  the  synthetic  production  of  the  latter 
substance.  0n§ , described  in  D.  R.  F.  15627b  consists  in  heating 
1 , 3-dinitro-2-methoxyanthra^uinone  with  sodium  methylate  in 
methyl  alcohol  solution  for  several  hours.  Some  preliminary 


11 


trials  that  were  made  with  this  method  showed  it  to  he  unsatis- 
factory. It  seems  that  the  1 , 3-dinitro-derivative , if  formed 
at  all  on  nitrating  2-methoxyanthraquinone , is  at  "best  only  a 

part  of  several  products.  A more  feasible  method  seemed  to  be 

17 

that  of  Bock  . The  latter  heated  anthragallol  with  sodium 
carbonate  in  nitrobenzene  until  the  sodium  salt  of  the  anthra- 
gallol was  formed.  Methyl  sulfate  was  then  added  and  the  heating 
continued.  On  cooling  the  filtered  solution  anthragallol  di- 
methyl ether  separated  in  crystalline  form.  This  was  converted 
into  its  sodium  salt  and  the  latter  heated  with  methyl  sulfate 
at  180°  in  order  to  complete  the  methylation  of  the  hydroxyl 
group  in  position  1.  This  method  was  tried  by  the  writer  but 
given  up  on  account  of  the  difficulty  of  handling  the  hot 
nitrobenzene  and  methyl  sulfate  solutions  and  also  because  Bock 
was  not  able  to  obtain  a pure  product  in  this  way. 

In  casting  about  for  a satisfactory  method  an  attempt 
was  next  made  to  condense  2,3,4-  or  3,4,5-trimethoxybenzoyl- 
benzoic  acid^,  obtained  by  Friedel  and  Crafts  reaction  from 
phthalic  anhydride  and  pyrogallcl  trimethyl  ether,  directly  to 
anthragallol  trimethyl  ether.  The  above  acid  was  prepared  in 
rather  poor  yield  and  on  this  account  ortho-anisoylbenzoic  acid 
was  prepared  for  use  in  determining  the  best  conditions  for 
carrying  on  the  further  condensation. 

The  best  method  previously  reported  for  the  prepara- 

19 

tion  of  ortho-anisoylbenzoic  acid  is  by  Meyer  and  Turnan  , who 
obtained  a 35,T  yield(  calculated  on  the  aniscl  used)  from  0.675 
mols  of  phthalic  anhydride,  0.79  mols  of  aniscl  and  0.71  of  a 


formula  weight  of  Aid 3 res.cting  in  15o  cc . of  nitrobenzene. 


' 


- 


The  latter,  they  found,  is  a much  better  solvent  for  phthalic 
anhydride  than  carbon  disulfide  and  consequently  assists  the 
reaction  considerably.  However  Meyer  and  Turnan  used  approximately 
only  one  mol  of  aluminium  chloride  whereas  Rubridge  and  qua~^ 
have  shown  that  in  reactions  involving  the  use  of  phthalic 
anhydride  two  formula  weights  of  A1C1._-  should  be  used  for  each  mol 
of  the  former,  that  is,  one  for  each  carbonyl  group.  When  the 
reaction  is  performed  in  this  manner  the  writer  has  obtained  a 
66/J  yield  of  ortho-anisoylbenzoic  acid. 

p. 

Lagodzinski  was  able  to  condense  3 ,4-dimethoxy , 
benzoylbenzoic  acid  to  hystazarin  dimethyl  ether  in  nearly 
quantitative  yield  by  short  heating  in  solution  in  concentrated 
sulfuric  acid  on  the  water  bath.  When  this  method  was  used  on 
ortho-anisoylbenzoic  acid  almost  complete  saponification  of  the 
methoxy  group  occurred,  no  doubt  due  to  the  fact  that  the  con- 
densing ring  hydrogen  atom  is  not  in  a reactive  xosition,  being 
rr.eta  to  the  methoxy  group. 

The  same  result  was  obtained  when  2,3,4-  or  3,4,5- 
trimethoxybenzoylbenzoic  acid  was  heated  on  the  water  bath  in- 
concentrated  sulfuric  acid  solution.  The  material  was  very 
readily  condensed  to  an  anthraquinone  compound  but  even  more 
easily  saponified  so  that  the  product  was  a partially  methylated 
anthragallcl . 

Finally  there  was  devised  a method  of  methylating 
anthragallcl  with  methyl  sulfate,  which,  while  extravagant  in  the 
amount  of  methyl  sulfate  required  was  convenient  in  manipulation 
and  gave  a product  of  good  quality. 

Reduction  of  anthragallol  trimethyl  ether  to  1,2,3- 


. 


■ 


j 


. 


13 


trimethoxyanthracene  was  first  tried  by  the  method  used  by 
Lagodzinski^  in  reducing  hystazarin  dimethyl  ether  to  2,3- 
dimethoxy anthracene , but  with  unsuccessful  results,  his  method 
involved  preparing  the  material  in  a very  fine  state  of  division 
and  then  treatment  with  zinc  dust  and  ammonia  with  continual 
shaking  and  heating  on  the  water  bath  for  several  hours.  No 
satisfactory  reduction  could  be  obtained  in  this  way  even  when 
the  process  was  continued  six  or  eight  hours  and  the  material 
kept  in  continual  agitation  with  a mechanical  stirring  device. 
After  many  trials  it  was  found  that  the  anthragallol  trimethyl 
ether  was  suitable  for  use  in  the  form  in  which  it  crystallized 
from  solution  and  that  the  reaction  proceeded  satisfactorily 
in  about  thirty  or  forty  minutes  time  only. 


14 


IV.  EXPERIMENTAL  PART. 

para-Nitrobromobenzene . 

A mixture  of  51  cc.  of  fuming  nitric  acid  (1.5)  and 
108  cc.  of  concentrated  sulfuric  acid  was  added  through  a dropping 
funnel  slowly  to  j-oo  grams  of  bromobenzene  kept  at  50°  on  the 
water  bath.  After  the  nitrating  mixture  was  all  added  the  temper- 
ature was  gradually  raised  to  120°  with  frequent  shaking.  The 
material  was  then  poured  into  water  and  filtered,  washed  free  from 
acid  and  then  dissolved  in  600  cc.  of  boiling  95$  alcohol  and 
allowed  to  cool.  The  crystalline  para-nitrobromobenzene  was 
filtered  off  and  a second  crop  obtained  on  concentrating  the 
solution.  Total  yield,  03  grams.  M.  P.  125°.  The  alcohol 
solution  on  evaporation  left  70  grams  of  impure  ortho-nitrobrcmo- 
benzene . 

O *1 

1 ,2-Dibromo-4-nitrobenzene . ‘-"t 

20  grams  of  para-nitrobromobenzene,  5 grams  of  anhy- 
drous ferric  chloride  and  6.4  cc . of  dry  bromine  were  sealed  in  a 
tube  and  heated  at  98°  for  50  hours.  The  dark  brown  liquid  was 
thrown  into  water  and  washed  free  from  ferric  chloride  and  acid. 

It  was  purified  by  distilling  under  reduced  pressure.  At  22  mm.. 

52  grams  were  collected  between  175c  and  185°.  This  solidified 
in  the  receiver.  It  was  crystallized  from  alcohol.  M.P.  57u. 

o o 

3 ,4-Dibromoaniline . 

50  grams  of  1 ,2-dibromo-4-nitrobenzene  were  mixed  ’with 


15 


one  liter  of  water  and  30  grams  of  iron  dust  and  kept  at  40u  while 
grams  of  concentrated  sulfuric  acid  were  added  a few  drops  at  a. 
time  over  a period  of  three  hours.  The  solution  was  made  alkaline 
and  the  base  was  extracted  with  ether  which  on  evaporation  left  a 
brown  oil  that  was  not  purified.  Yield,  40  grams. 

ortho-Dibromobenzene. 

105  grams  of  the  hydrochloride  of  the  base  obtained 
above  were  mixed  with  a solution  of  12C  cc.  of  hydrochloric  acid  r* 
(1.2)  in  95  cc . of  water.  The  mixture  was  cooled  in  an  ice  and 
water  bath  and  a saturated  solution  of  sodium  nitrite  added  slowly 
until  the  solution  contained  an  excess  of  free  nitrous  acid.  After 
about  forty-five  minutes  the  diazcnium  salt  suddenly  crystallized 
cut.  The  mass  was  poured  slowly  into  1500  cc.  of  boiling  95/j 
alcohol.  A rapid  evolution  of  nitrogen  followed.  Since  ortho- 
dibromobenzene  distils  readily  with  alcohol  vapor  it  had  to  be 
separated  by  dilution  with  water.  The  precipitated  oil  was  dis- 
tilled at  53  mm.  and  50  grams  collected.  E ,P.  130-132°. 

Attempt  to  condense  ortho-dibromobenzene 
with  tetrabromoethane . 

The  tetrabromoethane  used  was  dried,  over  calcium 
chloride  and  distilled  under  reduced  pressure  several  times.  It  was 
obtained  as  a colorless  oil  'which  boiled  at  i.C2°  at  2 mm.  .and  at 
65°  at  i mm. 

10  grams  of  ortho-dibromobenzene  and  14.7  grams  of 
tetrabromoethane  were  dissolved  in  100  cc . of  anhydrous  ether  and 


16 


4 grams  of  clean  sliced  sodium  added.  The  mixture  was  warmed  slight- 
ly and  showed  a fairly  vigorous  reaction.  A considerable  amount  of 
mono-hromoacetylene  was  evolved.  After  twenty-four  hours  the  ether 
was  distilled  off  and  left  a red  oil  which  still  contained  enough 
bromoacetylene  so  that  it  ignited  in  the  air.  The  red  liquid  was 
distilled  at  ordinary  pressure.  8 grams  of  ortho-dibromobenzene 
were  recovered  and  only  a trace  of  residue  left. 

The  experiment  was  repeated  with  the  modification  that 
the  tetrabromoethane  was  dissolved  in  a small  amount  of  anhydrous 
ether  and  dropped  slowly  into  the  other  materials  during  48  hours, 
meanwhile  the  mixture  was  kept  gently  boiling.  After  removal  of 
the  ether  the  oil  was  distilled  at  45  mm.  pressure.  16  grams  of 
the  two  oily  substances  came  over  between  110unand  130  . About 
0.1  gram  of  residue  was  left  in  the  flask.  This  was  dissolved  in 
benzene  and  filtered  with  a small  amount  of  charcoal.  A color  test 
with  picric  acid  gave  a negative  result. 

The  alifatic  compounds  in  the  distillate  were  destroyed 
with  sodium  ethylate  and  the  ortho-dibromobenzene  recovered  in  pure 
form. 

A similar  experiment  w as  performed  with  the  substitution 
of  "Natur  Cupfer  0"  for  sodium  as  the  condensing  agent . No  reaction 
occurred  when  the  materials  were  heated  at  16C°  for  two  hours. 

Reaction  of  succinic  anhydride 
and  alpha-naphthol . 


14  grams  of  alpha-naphthol,  1C  grams  of  succinic 


17 


anhydride  and  7 grams  of  freshly  fused  zinc  chloride  were  heated 
together  in  an  oil  bath  at  140°  for  fifteen  minutes.  The  material 
turned  into  a dark  red  rosin- like  mass  from  which  no  single 
crystalline  compound  could  be  obtained. 


alpha-IIydroxy-beta-Naphthoic.  acid . 

Sodium  naphthyl  oxide  was  made  by  dissolving  one  mol 
of  sodium  in  200  cc.  of  absolute  methyl  alcohol  and  adding  one  mol 
of  alpha-naphthol  in  solution  in  ICC  cc . of  absolute  methyl  alco- 
hol, and  then  evaporating  to  dryness  finally  under  reduced  pressure. 
The  solid  was  quickly  powdered  and  placed  in  a calorimeter  bomb 
modified  for  the  purpose  and  sealed  with  a lead  gasket.  The  bomb 
was  attached  to  a carbon  dioxide  tank  containing  liquid  carbon 
dioxide  and  the  carbon  dioxide  allowed  to  enter  it  slowly  until  the 
pressure  in  the  bomb  was  the  same  as  in  the  tank.  Considerable 
heat  was  evolved  making  it  necessary  to  cool  the  bomb  in  cold  water 
during  the  absorption,  otherwise  the  sodium  naphthyl  carbonate 
may  rearrange  and  cut  down  the  yield  on  account  of  the  following 


reaction : 


o "*■<«- 


,,  o 

C''  o >v<x_ 


The  temperature  of  the  bomb  was  not  allowed  to  rise  above  65 " . The 
contents  were  shaken  during  the  absorption  which  was  complete  in  a 
about  15  minutes. 

The  bomb  was  then  heated  in  an  oil  bath  at  135°  for 


four  hours  in  order  to  bring  about  the  rearrangement  of  sodium 


' 


I litJ  V i’l 


- 


16 


naphthyl  carbonate  to  sodium  alpha-hydroxy-beta-naphthoate . The 
dry  salt  obtained  was  nearly  white.  It  was  washed  with  a little 
ether  to  remove  traces  of  naphthcl,  then  dissolved  in  water  and 
acidified  with  sulfuric  acid.  The  free  acid  which  was  obtained 
was  nearly  white  and  melted  at  20C-2C20.  Yield,  170  grams,  90% 
of  the  theory.  A sample  was  purified  by  charcoal  treatment  in 
alcohol  solution  and  then  recrystallized  from  the  alcohol.  It 
melted  at  206-9°,  and  remained  constant  at  that  point  after 
successive  crystallizations  from  alcohol,  benzene  and  ligroine . 
Various  melting  points  have  been  reported  in  the  literature,  the 

o rz 

highest  being  by  Anschutz’00  as  191-2°. 

al pha-Me thoxy -beta- naph tho i c acid. 

60  grams  of  alpha-hydroxy-beta-naphthoio  acid  and  13.8 
grams  of  sodium  were  dissolved  in  200  cc.  of  methyl  alcohol  and 
boiled  under  a reflux  condenser.  76  grains  of  methyl  sulfate  were 
added  in  small  portions  through  the  condenser.  The  product  was 
thrown  out  by  adding  water  and  extracted  with  cold  dilute  sodium 
hydroxide.  The  insoluble  material,  was  then  distilled  and  the 
fraction  boiling  from  188°  to  195°  at  18  mm.  was  collected  and 
crystallized  from  dilute  alcohol.  Later  work  showed  that  this 
sample  was  not  pure, methyl  ester  of  methoxynaphthoic  acid. 

It  was  readily  hydrolyzed  by  boiling  with  dilute 
sodium  hydroxide  solution.  The  acid  which  was  precipitated  when 
the  alkaline  solution  was  acidified  was  recrystallized  several 
times  from  benzene  and  then  from  alcohol.  A sample  was  obtained 
which  melted  at  123-  4°  and  was  shown  by  analysis  to  be  methcxy- 


19 


naphthoic  aoid. 

v . 1432  grams  of  substance  gave  0.3756  grams  of  carbon  dioxide 
and  0.0663  grams  cf  water. 

Calculated  for  Cb.-H^O-^,  C=71.25$,  H=4.98)£.  Found,  C=7i.53/C, 

H=5 .18$. 

In  view  of  the  fact  that  impure  compounds  were  used 
an  account  of  the  further  work  along  this  line  is  of  no  value. 

orthc-Anisoylbenzoic  acid. 

29  grams  (0.2  mol)  of  phthalic  anhydride,  22  grams 
(0,2  mol)  of  anisol  and  50  cc.  of  nitrobenzene  were  mixed  and  war m3 
until  solution  was  complete.  Then  53  grams  (0.4  mol  as  AlClg)  of 
aluminium  chloride  were  added  at  one  time.  The  reaction  took  place 
rapidly  with  violent  evolution  of  hydrogen  chloride  and  appeared  to 
be  complete  in  about  five  minutes.  It  'was  heated  on  the  steam  bath 
however,  for  about  twenty  minutes.  Water  and  hydrochloric  acid 
were  then  added  and  the  mixture  steam  distilled  until  all  the 
nitrobenzene  and  unchanged  anisol  were  removed.  The  oily  residue 
was  extracted  with  dilute  ammonia  in  which  nearly  all  dissolved. 

The  ammoniacal  solution  was  treated  with  dilute  hydrochloric  acid 
until  it  was  nearly  neutralized  and  a small  quantity  of  black  tar 
which  came  out  was  filtered  off.  The  filtrate  which  was  nearly 
colorless  was  entirely  acidified  with  hydrochloric  acid  which 
threw  down  an  oil  that  quickly  solidified.  The  material  was 
recrystallized  from  alcohol  and  obtained  as  a white  substance, 

M.P.  148°.  The  yield  was  34  grams  or  66$  cf  the  theory. 


. 


. 

. 

' 


20 


Attempt  to  condense  ortho-aniscylbenzoic  acid  to 
3-methoxyanthraquinone . 

20  grams  of  ortho-anisoylbenzoylbenzoic  acid  were 
dissolved  in  100  cc . of  concentrated  sulfuric  acid  and  heated  on 
the  water  bath  for  two  hours.  The  solution  was  poured  onto  cracked 
ice  and  the  precipitated  material  washed  and  warmed  with  dilute 
ammonia.  Al}.  but  a trace  of  the  substance  dissolved.  The  insol- 
uble part  was  crystallized  from  hot  alcohol  and  gave  less  than  0.1 
gram  of  yellow  needles  -which  were  3-methoxyanthraquinone.  The 
ammoniacal  solution  was  acidified  and  the  precipitated  material 
crystallized  from  50 % alcohol.  There  was  obtained  in  this  way  10 
grams  of  slightly  colored  material  which  melted  at  143c  and  was  the 
unchanged  original  substance.  The  37hydroxyanthraquinone  in  the 
mother  liquor  was  not  isolated. 

2,3,4-  or  3 , 4 , 5- trimethoxybenzoy lbenzoic  acid. 

The  pyrogallol  trimethyl  ether  used  in  this  experiment 
was  prepared  by  treating  pyrogallol  in  sodium  hydroxide  solution 
with  methyl  sulfate  according  to  the  method  of  Bargellini  and 

24  pc 

Leda^  and  of  UHmann"0  . From  126  grams  of  pyrogallol  there  was 

o 

obtained  00  grams  of  the  trimethyl  ether  boiling  between  235  and 
237°. 

15  grams  (0.1  mol)  of  phthalic  anhydride,  17  grams 
( 0 . 1 mol)  of  pyrogallol  trimethyl  ether  and  35  cc.  of  nitrobenzene 
were  mixed  and  warmed  until  the  anhydride  was  dissolved.  Then  27 
grams  (0.2  mol  as  A1C1-)  of  aluminium  chloride  were  added  at  one 
time.  The  reaction  proceeded  rapidly  for  about  five  minutes  end 


* 


21 


was  then  completed  by  twenty  minutes  warming  on  the  water  bath. 

After  adding  water  and  hydrochloric  acid  and  steaming  out  the 
nitrobenzene  the  oily  residue  was  extracted  with  warm  dilute 
ammonia.  The  dark  colored  ammonia  solution  was  neutralized  with 

I 

dilute  hydrochloric  acid,  a few  drops  in  excess  added  and  the 
solution  boiled  with  charcoal  and  filtered.  The  material  was  then 
completely  precipitated  with  hydrochloric  acid  and  a solid  obtained. 
This  was  collected  and  crystallized  from  dilute  alcohol.  Neaply 
white  crystals.  Yield,  3 grams  or  9.5 %.  M.P.  169°. 

Attempt  to  condense  2,3,  4-  or  3 ,4 , 5-trimethoxybenzoyl- 
benzoic  acid  to  anthragallol  trimethyl  ether. 

5 grams  of  2,3,4-  or  3 ,4^5-trimethoxybenzoylbenzoic 
acid  were  dissolved  in  25  cc.  of  concentrated  sulfuric  acid  and 
heated  on  the  water  bath  for  ten  minutes  with  constant  shaking  and 
then  poured  onto  cracked  ice.  The  precipitated  material  was  en- 
tirely soluble  in  alkali.  On  fractional  crystallization  from 
glacial  acetic  acid  it  yielded  two  indefinitely  melting  fractions, 
one  at  about  156°  and  the  other  above  3i0°. 

Preparation  of  anthragallol. 

4CC  grams  of  gallic  acid,  800  grams  of  benzoic  acid  and 
4350  cc.  of  concentrated  sulfuric  acid  were  placed  in  a ten  liter 
flask  and  gradually  heated  to  140°  during  three  and  one  half  hours 
time  and  then  maintained  at  that  temperature  two  hours  longer.  The 
solution  was  then  cooled,  poured  into  ice  water,  filtered  and 
washed  with  water.  The  precipitated  material  was  composed  of 


22 


anthragallol,  ruffigallic  acid,  a little  black  oxidized  substance 
and  a considerable  amount  of  benzoic  acid.  It  was  made  into  a paste 
with  water  and  treated  with  concentrated  ammonia  sufficient  to 
convert  the  benzoic  acid  into  its  salt.  The  formation  of  the  blue- 
black  salt  of  anthragallol  serves  as  an  indicator  for  the  end-point 
of  the  reaction.  The  substance  was  then  filtered  and  well  washed 
with  boiling  water.  Portions  of  the  dark  brown  filter  cake  were  then 
extracted  with  boiling  alcohol,  which  dissolves  the  anthragallol  and 
not  the  ruffigallic  acid,  and  the  alcohol  solution  allowed  to  cool. 
Red-brown  to  chocolate-brown  crystals  were  obtained  according  to 
the  rate  at  which  the  solution  cooled.  Occasionally  the  color  was 
a light  yellow-red.  The  yield  was  about  40 % of  theory.  M.P .320°oorr. 

The  inethylation  of  anthragallol. 

10  grams  of  anthragallol  were  covered  with  ICO  cc.  of 
methyl  alcohol  in  a flask  connected  with  a reflux  condenser  and  also 
a dropping  funnel.  The  methyl  alcohol  was  kept  continually  boiling 
while  50/b  potassium  hydroxide  solution  in  water  was  added  in  small 
portions  through  the  condenser  alternating  with  small  portions  of 
methyl  sulfate  through  the  dropping  funnel.  130  cc.  of  methyl 
sulfate  were  added,  a methyl  sulfate  portion  being  added  last  so 
that  the  material  was  left  in  the  form  of  a yellow  partially 
methylated  anthragallol  which  mostly  crystallized  out  of  the  hot 
aolution.  Two  volumes  of  water  were  added  and  the  mixture  cooled 
and  filtered.  The  yellow  crystalline  material  'was  covered  as  before 
with  IOC  cc.  of  methyl  alcohol  and  given  the  same  treatment  using, 
however,  only  50  cc.  of  additional  methyl  sulfate.  The  product  from 


23 


this  treatment  was  isolated  as  above  and  dissolved  in  200  co.  of 
boiling  benzene.  The  benzene  solution  was  poured  into  200  cc.  of 
aqueous  solution  of  sodium  hydroxide  which  had  been  warmed  to 
60°  and  the  two  shaken  together.  The  partially  methylated 
material  formed  an  insoluble  red  crystalline  sodium  salt.  The 
mixed  solvents  were  then  filtered  from,  the  sodium  salt,  the  latter 
washed  with  hot  benzene,  and  the  benzene  solution  separated  from 
the  aqueous  layer.  The  benzene  was  then  distilled  from  the  solution 
of  the  trimethyl  ether  and  the  latter  transferred  to  a small  beaker 
by  dissolving  in  boiling  glacial  acetic  acid  (10-15  cc.).  100  cc. 

of  alcohol  were  then  added  to  this  hot  solution  and  the  mixture 
stirred.  Within  a moment  the  solution  became  thick  and  pasty  with 
fine  needle-like  yellow  crystals  of  anthragallol  trimethyl  ether, 
which  were  filtered  off  and  dried.  Yield,  5.6  grams,  50^  of  the 
theory.  M.P.  173°.  The  dimethyl  ether  obtained  as  sodium  salt  was 
then  further  treated  as  above  or  as  follows. 


Silver  oxide  and  methyl  iodide  method. 


5.5  grams  of  the  dimethyl  ether,  8 grams  of  silver  oxide 
and  20  cc.  of  methyl  iodide  were  boiled  together  for  twenty  hours. 

On  separating  the  di-  and  tri-ethers  in  the  same  way  as  above  there 
was  obtained  2.6  grams  of  the  trimethyl  ether. 

Anthragallol  itself  cannot  be  satisfactorily  methylated 
from  the  beginning  with  silver  oxide  and  methyl  iodide  since  there 
is  too  much  oxidation  of  the  anthragallol. 


■mxxrrxr  rm.TJ'ixrrzz 


24 

Reduction  of  anthragallol  trimethyl  ether  to 
1 ,2 , 3- trimethoxy anthracene  . 

5 grams  of  anthragallol  trimethyl  ether  were  suspended 
in  a mixture  of  ICO  cc.  of  concentrated  ammonia  water  and  200  cc . 
of  water.  25  grams  of  zinc  dust  were  added  and  the  mixture  heated 
on  the  water  hath  with  continual  shaking  and  rotating  for  forty 
minutes.  Within  five  minutes  a deep  red  color  developed  in  the 
solution.  This  gradually  disappeared  until  at  the  end  the  clear 
solution  was  straw  color.  The  mixture  was  then  cooled  and 
filtered  and  the  zinc  residue  extracted  with  about  100  cc.  of 
boiling  alcohol.  The  alcohol  solution  was  evaporated  to  a small 
volume,  about  25  cc.  of  glacia}.  acetic  acid  added,  heated  to 
boiling,  and  water  added  drop  by  drop  while  scratching  the  side 
of  the  beaker  and  allowing  it  to  cool.  A crop  of  nearly  colorless 
prisms  amounting  to  1.6  grams  was  obtained.  On  recrystallizing 
from  acetic  acid  and  a little  water  1.4  grams  were  obtained  which 
consisted  of  colorless  crystals  having  a blue-green  fluorescent 
cast.  The  melting  point  remained  constant  at  01-2°  through 
several  crystallizations.  In  alcohol  solution  the  material  was 
strongly  fluorescent. 

O.j.306  grams  gave  0.3650  grams  of  CO.?  and  0.C734  grams  of  H?0. 
0.1291  grams  gave  C.36C1  grams  of  CO?  and  0.0757  grams  of  H2O. 
Calculated  for  Ci7Hi603,  C=76.G9£,  H=6.02^. 

Found,  C=76.iG/£  and  76.07^.  H=6.26^o  and  6.56/S. 

Since  all  the  intermediate  reduction  products  of 


anthraquinone  will  react  in  one  way  or  another  with  the  Grignard 


. 


25 

reagent the  material  was  tested  in  this  way.  On  adding  the 
substance  to  a solution  of  methyl  magnesium  iodide  there  was  no 
evidence  of  a reaction.  The  mixture  was  boiled  a time  and 
decomposed  as  usual . Much  methane  was  evolved  and  the  xjr>ecipitated 
substance  was  found  to  be  the  original  material. 

1,2 , 37  trihydroxy anthracene . 

0.87  gram  of  I 3- trimethoxy anthracene  was  warmed 
gently  with  ±.0  cc.  of  57 % hydr iodic  acid  for  thirty  minutes  during 
the  time  that  methyl  iodide  was  distilled  out.  The  solution  was  de- 
colorized with  sodium  bisulfite  and  filtered.  A solid  black 
material  was  collected.  It  was  soluble  in  alkali  with  a dark  brown 
color.  A portion  was  crystallized  from  benzene  but  oxidation  in 
solution  and  in  drying  turned  the  substance  dark  brown. 

The  investigation  of  this  substance  will  be  continued 
in  the  future. 


* 

. 


. 


. . 


27 


VITA. 

The  writer  was  born  in  Chattanooga,  Tennessee,  July 
2,  1889.  His  early  education  was  received  in  the  public  schools 
of  Clarke  and  Green  Counties  in  Ohio.  In  1908  he  entered  Earlham 
College,  Richmond,  Indiana,  and  was  graduated  from  that  institution 
in  1912.  The  same  year  he  entered  the  Graduate  School  of  the 
University  of  Illinois  and  continued  there  for  three  years  as  a 
student  and  assistant  in  the  Chemistry  Department.  He  received 
the  Master  of  Science  degree  in  1914.  From  1915  to  1917  he  was 
an  assistant  and  a fellow  on  the  staff  of  the  Rockefeller 
Institute  for  Medical  Research.  From  1917  to  1919  he  was  research 
chemist  and  director  of  chemical  research  work  for  Eli  Lilly  and 
Company  of  Indianapolis,  Indiana.  From  1919  until  the  present 
time  he  has  been  director  of  the  Chemistry  Department  at 
Earlham  College. 

ACKNOWLEDGEMENT . 

The  writer  wishes  to  express  .to  Professor  W.  A.  Noyes 


his  sincere  appreciation  for  the  suggestions  and  encouragement 
which  have  inspired  him  in  the  carrying  on  of  this  research. 


